Controlled-release of tetracycline and lovastatin by poly(D,L-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs

Next-generation antibacterial nanopolymers for treating oral chronic inflammatory diseases of bacterial origin

BACKGROUND

'Periodontitis' refers to periodontal destruction of connective tissue attachment and bone, in response to microorganisms forming subgingival biofilms on the root surface, while 'apical periodontitis' refers to periapical inflammatory processes occurring in response to microorganisms within the root canal system. The treatment of both diseases is based on the elimination of the bacterial challenge, though its predictability depends on the ability of disrupting these biofilms, what may need adjunctive antibacterial strategies, such as the next-generation antibacterial strategies (NGAS). From all the newly developed NGAS, the use of polymeric nanotechnology may pose a potential effective approach. Although some of these strategies have only been tested in vitro and in preclinical in vivo models, their use holds a great potential, and therefore, it is relevant to understand their mechanism of action and evaluate their scientific evidence of efficacy.

OBJECTIVES

To explore NGAS based on polymeric nanotechnology used for the potential treatment of periodontitis and apical periodontitis.

METHOD

A systemic search of scientific publications of adjunctive antimicrobial strategies using nanopolymers to treat periodontal and periapical diseases was conducted using The National Library of Medicine (MEDLINE by PubMed), The Cochrane Oral Health Group Trials Register, EMBASE and Web of Science.

RESULTS

Different polymeric nanoparticles, nanofibres and nanostructured hydrogels combined with antimicrobial substances have been identified in the periodontal literature, being the most commonly used nanopolymers of polycaprolactone, poly(lactic-co-glycolic acid) and chitosan. As antimicrobials, the most frequently used have been antibiotics, though other antimicrobial substances, such as metallic ions, peptides and naturally derived products, have also been added to the nanopolymers.

CONCLUSION

Polymeric nanomaterials containing antimicrobial compounds may be considered as a potential NGAS. Its relative efficacy, however, is not well understood since most of the existing evidence is derived from in vitro or preclinical in vivo studies.

Gold Nanoparticles Confined in Mesoporous Bioactive Glass for Periodontitis Therapy

Periodontitis is a chronic disease caused by bacterial infection and is characterized with alveolar bone resorption. Bone regeneration in periodontitis remains a critical challenge because bacterial infection induced an unfavorable microenvironment for osteogenesis. Therefore, it is necessary to design proper therapeutic platforms to control bacterial infection and promote bone regeneration. Herein, mesoporous bioactive glass (MBG) with different pore sizes (3.0, 4.3, and 12.3 nm) was used as an in situ reactor to confine the growth of gold nanoparticles (Au NPs), forming MBG@Au hybrids which combine the osteoconductivity of MBG and antibacterial properties of Au NPs. Upon near-infrared (NIR) irradiation, the MBG@Au NPs showed efficient antibacterial properties both in vitro and in vivo. Besides, the osteogenesis properties of MBG@Au also improved under NIR irradiation. Furthermore, the in vivo results demonstrated that MBG@Au can effectively promote alveolar bone regeneration and realize the healing of serious periodontitis.

Chitosan nanoparticle applications in dentistry: a sustainable biopolymer

The epoch of Nano-biomaterials and their application in the field of medicine and dentistry has been long-lived. The application of nanotechnology is extensively used in diagnosis and treatment aspects of oral diseases. The nanomaterials and its structures are being widely involved in the production of medicines and drugs used for the treatment of oral diseases like periodontitis, oral carcinoma, etc. and helps in maintaining the longevity of oral health. Chitosan is a naturally occurring biopolymer derived from chitin which is seen commonly in arthropods. Chitosan nanoparticles are the latest in the trend of nanoparticles used in dentistry and are becoming the most wanted biopolymer for use toward therapeutic interventions. Literature search has also shown that chitosan nanoparticles have anti-tumor effects. This review highlights the various aspects of chitosan nanoparticles and their implications in dentistry.

Barrier membranes for periodontal guided bone regeneration: a potential therapeutic strategy

Periodontal disease is one of the most common oral diseases with the highest incidence world-wide. In particular, the treatment of periodontal bone defects caused by periodontitis has attracted extensive attention. Guided bone regeneration (GBR) has been recognized as advanced treatment techniques for periodontal bone defects. GBR technique relies on the application of barrier membranes to protect the bone defects. The commonly used GBR membranes are resorbable and non-resorbable. Resorbable GBR membranes are divided into natural polymer resorbable membranes and synthetic polymer resorbable membranes. Each has its advantages and disadvantages. The current research focuses on exploring and improving its preparation and application. This review summarizes the recent literature on the application of GBR membranes to promote the regeneration of periodontal bone defects, elaborates on GBR development strategies, specific applications, and the progress of inducing periodontal bone regeneration to provide a theoretical basis and ideas for the future application of GBR membranes to promote the repair of periodontal bone defects.

Repurposing sarecycline for osteoinductive therapies: an in vitro and ex vivo assessment

INTRODUCTION

Tetracyclines (TCs) embrace a class of broad-spectrum antibiotics with unrelated effects at sub-antimicrobial levels, including an effective anti-inflammatory activity and stimulation of osteogenesis, allowing their repurposing for different clinical applications. Recently, sarecycline (SA)-a new-generation molecule with a narrower antimicrobial spectrum-was clinically approved due to its anti-inflammatory profile and reduced adverse effects verified with prolonged use. Notwithstanding, little is known about its osteogenic potential, previously verified for early generation TCs.

MATERIALS AND METHODS

Accordingly, the present study is focused on the assessment of the response of human bone marrow-derived mesenchymal stromal cells (hBMSCs) to a concentration range of SA, addressing the metabolic activity, morphology and osteoblastic differentiation capability, further detailing the modulation of Wnt, Hedgehog, and Notch signaling pathways. In addition, an ex vivo organotypic bone development system was established in the presence of SA and characterized by microtomographic and histochemical analysis.

RESULTS

hBMSCs cultured with SA presented a significantly increased metabolic activity compared to control, with an indistinguishable cell morphology. Moreover, RUNX2 expression was upregulated 2.5-fold, and ALP expression was increased around sevenfold in the presence of SA. Further, GLI2 expression was significantly upregulated, while HEY1 and HNF1A were downregulated, substantiating Hedgehog and Notch signaling pathways' modulation. The ex vivo model developed in the presence of SA presented a significantly enhanced collagen deposition, extended migration areas of osteogenesis, and an increased bone mineral content, substantiating an increased osteogenic development.

CONCLUSION

Summarizing, SA is a promising candidate for drug repurposing within therapies envisaging the enhancement of bone healing/regeneration.

A multifunctional drug consisting of tetracycline conjugated with odanacatib for efficient periodontitis therapy

The treatment of periodontitis can be very challenging due to its complex etiologies. A new pharmacologic strategy entitled “host-modulation therapy,” has been introduced to improve periodontal treatment outcomes. Supposedly, a multifunctional drug with the potential for bacterial infection prevention, host-response modulation and bone healing promotion would be a promising option for periodontitis therapy, but related studies remain substantially lacking. In this study, we successfully conjugated tetracycline with odanacatib (a selective inhibitor of cathepsin K) to construct a multifunctional drug (TC-ODN). We discovered that TC-ODN could promote macrophages polarizing toward anti-inflammatory phenotype and promote osteogenesis of PDLSCs under inflammatory microenvironment. In vivo, TC-ODN could be absorbed and distributed specifically to the bone after systemic administration, and accumulation of TC-ODN increased bone mineral density in ovariectomized rats. Importantly, periodontal administration of TC-ODN could successfully promote bone healing in periodontitis rats with alveolar bone loss. The findings in our study uncovered the excellent biocompatibility and multifunction of TC-ODN, including bone-targeted accumulation, immunoregulation, anti-inflammatory activity and promotion of bone healing, which might contribute to the clinical treatment of periodontitis.

Future Drug Targets in Periodontal Personalised Medicine—A Narrative Review

Periodontal disease is an infection-driven inflammatory disease characterized by the destruction of tooth-supporting tissues. The establishment of chronic inflammation will result in progressive destruction of bone and soft tissue changes. Severe periodontitis can lead to tooth loss. The disease has complex pathogenesis with an interplay between genetic, environmental, and host factors and pathogens. Effective management consists of plaque control and non-surgical interventions, along with adjuvant strategies to control inflammation and disrupt the pathogenic subgingival biofilms. Recent studies have examined novel approaches for managing periodontal diseases such as modulating microbial signaling mechanisms, tissue engineering, and molecular targeting of host inflammatory substances. Mounting evidence suggests the need to integrate omics-based approaches with traditional therapy to address the disease. This article discusses the various evolving and future drug targets, including proteomics, gene therapeutics, vaccines, and nanotechnology in personalized periodontal medicine for the effective management of periodontal diseases.

Hydrophobic Composites Designed by a Nonwoven Cellulose-Based Material and Polymer/CaCO3 Patterns with Biomedical Applications

Herein, we report a simple method to obtain hydrophobic surfaces by surface modification with calcium carbonate via diffusion-controlled crystallization using a cheap, versatile, and super-hydrophilic cellulose-based nonwoven material (NWM) as the substrate. To control the CaCO₃ crystal growth, the ammonium carbonate diffusion method was applied in the presence of polyanions [poly(acid acrylic), poly(2-acrylamido-2-methylpropanesulfonic acid), and a copolymer which contains 55 mol % 2-acrylamido-2-methylpropanesulfonic acid and 45 mol % acrylic acid] or nonstoichiometric polyelectrolyte complexes with polycations [poly(allylamine hydrochloride) and chitosan] on a pristine NWM and on polycation-treated surfaces. The surface morphology obtained by calcite growth under surface or environmental functional groups' influence and the hydrophilic/hydrophobic character of the composite materials were followed and compared to that of the starting material. The obtained composite materials become hydrophobic, having a contact angle in the range of 110-135°. The capacity of tetracycline sorption and release by selected modified surfaces were followed and compared to the untreated NWM. Also, the biological properties were evaluated in terms of biocompatibility, antibacterial activity, and antifouling capability.

Periodontal Bifunctional Biomaterials: Progress and Perspectives

Periodontitis is a chronic infectious disease that destroys periodontal supportive tissues and eventually causes tooth loss. It is attributed to microbial and immune factors. The goal of periodontal therapy is to achieve complete alveolar bone regeneration while keeping inflammation well-controlled. To reach this goal, many single or composite biomaterials that produce antibacterial and osteogenic effects on periodontal tissues have been developed, which are called bifunctional biomaterials. In this review, we summarize recent progress in periodontal bifunctional biomaterials including bioactive agents, guided tissue regeneration/guided bone regeneration (GTR/GBR) membranes, tissue engineering scaffolds and drug delivery systems and provide novel perspectives. In conclusion, composite biomaterials have been greatly developed and they should be chosen with care due to the risk of selection bias and the lack of evaluation of the validity of the included studies.

Polysaccharide-Based Drug Delivery Systems for the Treatment of Periodontitis

Periodontal diseases are worldwide health problems that negatively affect the lifestyle of many people. The long-term effect of the classical treatments, including the mechanical removal of bacterial plaque, is not effective enough, causing the scientific world to find other alternatives. Polymer-drug systems, which have different forms of presentation, chosen depending on the nature of the disease, the mode of administration, the type of polymer used, etc., have become very promising. Hydrogels, for example (in the form of films, micro-/nanoparticles, implants, inserts, etc.), contain the drug included, encapsulated, or adsorbed on the surface. Biologically active compounds can also be associated directly with the polymer chains by covalent or ionic binding (polymer-drug conjugates). Not just any polymer can be used as a support for drug combination due to the constraints imposed by the fact that the system works inside the body. Biopolymers, especially polysaccharides and their derivatives and to a lesser extent proteins, are preferred for this purpose. This paper aims to review in detail the biopolymer-drug systems that have emerged in the last decade as alternatives to the classical treatment of periodontal disease.

Engineering Polymeric Nanosystems against Oral Diseases

Nanotechnology and nanoparticles (NPs) are at the forefront of modern research, particularly in the case of healthcare therapeutic applications. Polymeric NPs, specifically, hold high promise for these purposes, including towards oral diseases. Careful optimisation of the production of polymeric NPs, however, is required to generate a product which can be easily translated from a laboratory environment to the actual clinical usage. Indeed, considerations such as biocompatibility, biodistribution, and biodegradability are paramount. Moreover, a pre-clinical assessment in adequate in vitro, ex vivo or in vivo model is also required. Last but not least, considerations for the scale-up are also important, together with an appropriate clinical testing pathway. This review aims to eviscerate the above topics, sourcing at examples from the recent literature to put in context the current most burdening oral diseases and the most promising polymeric NPs which would be suitable against them.

Influence of Materials Properties on Bio-Physical Features and Effectiveness of 3D-Scaffolds for Periodontal Regeneration

Periodontal diseases are multifactorial disorders, mainly due to severe infections and inflammation which affect the tissues (i.e., gum and dental bone) that support and surround the teeth. These pathologies are characterized by bleeding gums, pain, bad breath and, in more severe forms, can lead to the detachment of gum from teeth, causing their loss. To date it is estimated that severe periodontal diseases affect around 10% of the population worldwide thus making necessary the development of effective treatments able to both reduce the infections and inflammation in injured sites and improve the regeneration of damaged tissues. In this scenario, the use of 3D scaffolds can play a pivotal role by providing an effective platform for drugs, nanosystems, growth factors, stem cells, etc., improving the effectiveness of therapies and reducing their systemic side effects. The aim of this review is to describe the recent progress in periodontal regeneration, highlighting the influence of materials' properties used to realize three-dimensional (3D)-scaffolds, their bio-physical characteristics and their ability to provide a biocompatible platform able to embed nanosystems.

Chitosan Nanoparticles-Insight into Properties, Functionalization and Applications in Drug Delivery and Theranostics

Nanotechnology-based development of drug delivery systems is an attractive area of research in formulation driven R&D laboratories that makes administration of new and complex drugs feasible. It plays a significant role in the design of novel dosage forms by attributing target specific drug delivery, controlled drug release, improved, patient friendly drug regimen and lower side effects. Polysaccharides, especially chitosan, occupy an important place and are widely used in nano drug delivery systems owing to their biocompatibility and biodegradability. This review focuses on chitosan nanoparticles and envisages to provide an insight into the chemistry, properties, drug release mechanisms, preparation techniques and the vast evolving landscape of diverse applications across disease categories leading to development of better therapeutics and superior clinical outcomes. It summarizes recent advancement in the development and utility of functionalized chitosan in anticancer therapeutics, cancer immunotherapy, theranostics and multistage delivery systems.

Construction of a Mesoporous Polydopamine@GO/Cellulose Nanofibril Composite Hydrogel with an Encapsulation Structure for Controllable Drug Release and Toxicity Shielding

The development of intelligent and multifunctional hydrogels having photothermal properties, good mechanical properties, sustained drug release abilities with low burst release, antibacterial properties, and biocompatibility is highly desirable in the biomaterial field. Herein, mesoporous polydopamine (MPDA) nanoparticles wrapped with graphene oxide (GO) were physically cross-linked in cellulose nanofibril (CNF) hydrogel to obtain a novel MPDA@GO/CNF composite hydrogel for controllable drug release. MPDA nanoparticles exhibited a high drug loading ratio (up to 35 wt %) for tetracycline hydrochloride (TH). GO was used to encapsulate MPDA nanoparticles for extending the drug release time and reinforcing the physical strength of the obtained hydrogel. The mechanical strength of the as-fabricated MPDA@GO/CNF composite hydrogel was five times greater compared to that of the pure CNF hydrogel. Drug release experiments demonstrated that burst release behavior was significantly reduced by adding MPDA@GO. The drug release time of the MPDA@GO/CNF composite hydrogel was 3 times and 7.2 times longer than that of the polydopamine/CNF hydrogel and pure CNF hydrogel, respectively. The sustained and controlled drug release behaviors of the composite hydrogel were highly dependent on the proportion of MPDA and GO. Moreover, the rate of drug release could be accelerated by near-infrared (NIR) light irradiation and pH value change. The drug release kinetics of the as-prepared composite hydrogel was well described by the Korsmeyer-Peppas model, and the drug release mechanism of TH from the composite hydrogel was anomalous transport. Importantly, this carefully designed MPDA@GO/CNF composite hydrogel showed good biocompatibility through an in vitro cytotoxicity test. In particular, the toxicity of GO was well shielded by the CNF hydrogel. Therefore, this novel MPDA@GO/CNF composite hydrogel with an encapsulation structure for controllable drug release and toxicity shielding of GO could be used as a very promising controlled drug delivery carrier, which may have potential applications for chemical and physical therapies.

Nanofibrous asymmetric collagen/curcumin membrane containing aspirin-loaded PLGA nanoparticles for guided bone regeneration

The goal of the current study was to develop an asymmetric guided bone regeneration (GBR) membrane benefiting from curcumin and aspirin. The membrane was prepared using electrospinning technique and then was physic-chemically characterized by the conventional methods. The release profile of aspirin from the prepared membrane was also measured by ultraviolet spectrophotometry. Also, the antibacterial activities of the membrane was evaluated. We also assessed the in vitro effects of the prepared membrane on the biocompatibility and osteogenic differentiation of dental pulp stem cells (DPSCs), and evaluated in vivo bone regeneration using the prepared membrane in the defects created in both sides of the dog’s jaw by histology. The results from the characterization specified that the membrane was successfully prepared with monodispersed nanosized fibers, uniform network shaped morphology, negative surface charge and sustained release platform for aspirin. The membrane also showed antimicrobial effects against all tested bacteria. The presence of curcumin and aspirin in the asymmetric membrane enhanced osteogenic potential at both transcriptional and translational levels. The results of the animal test showed that the test area was completely filled with new bone after just 28 days, while the commercial membrane area remained empty. There was also a soft tissue layer above the new bone area in the test side. We suggested that the prepared membrane in this work could be used as a GBR membrane to keep soft tissue from occupying bone defects in GBR surgeries. Besides, the surgeries can be benefited from antibacterial activities and bone healing effects of this novel GBR membrane while, simultaneously, promoting bone regeneration.

Tooth-Supporting Hard Tissue Regeneration Using Biopolymeric Material Fabrication Strategies

The mineralized tissues (alveolar bone and cementum) are the major components of periodontal tissues and play a critical role to anchor periodontal ligament (PDL) to tooth-root surfaces. The integrated multiple tissues could generate biological or physiological responses to transmitted biomechanical forces by mastication or occlusion. However, due to periodontitis or traumatic injuries, affect destruction or progressive damage of periodontal hard tissues including PDL could be affected and consequently lead to tooth loss. Conventional tissue engineering approaches have been developed to regenerate or repair periodontium but, engineered periodontal tissue formation is still challenging because there are still limitations to control spatial compartmentalization for individual tissues and provide optimal 3D constructs for tooth-supporting tissue regeneration and maturation. Here, we present the recently developed strategies to induce osteogenesis and cementogenesis by the fabrication of 3D architectures or the chemical modifications of biopolymeric materials. These techniques in tooth-supporting hard tissue engineering are highly promising to promote the periodontal regeneration and advance the interfacial tissue formation for tissue integrations of PDL fibrous connective tissue bundles (alveolar bone-to-PDL or PDL-to-cementum) for functioning restorations of the periodontal complex.

Comparative evaluation of 2% turmeric extract with nanocarrier and 1% chlorhexidine gel as an adjunct to scaling and root planing in patients with chronic periodontitis: A pilot randomized controlled clinical trial

Context

Nanoparticles, owing to their smaller size, penetrate regions inaccessible to other delivery systems, such as periodontal pockets. Thus, the present study aimed to comparatively evaluate efficacy of 2% curcumin with nanocarrier and 1% chlorhexidine gel as a local drug delivery (LDD) in the treatment of periodontal pockets.

Materials and Methods

Forty-five chronic periodontitis patients with pocket depth 5-7 mm in two or more teeth were selected. Full-mouth scaling and root planing (SRP) was done for all patients followed by random allocation to the three treatment groups, namely SRP group (Group 1), 2% curcumin with nanogel (Group 2), and 1% chlorhexidine gel (Group 3). Clinical parameter assessment and microbiological analysis of subgingival plaque samples for Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythia (Tf) was done at baseline, 21^st day, and 45^th day.

Results

The results showed that when the two LDD agents were used as an adjunct to SRP in chronic periodontitis, there was an improvement in all clinical parameters. Evaluation of microbiological parameters also showed a significant reduction in Aa, Pg, and Tf levels. Comparison of 2% turmeric extract with a nanocarrier system with 1% chlorhexidine gel showed that both the agents had a comparable antibacterial effect on the three selected periodontopathic bacteria.

Conclusion

The present study showed that both the LDD agents showed an effective improvement of clinical and microbiologic parameters. 2% curcumin delivered with a nanocarrier system showed results comparable to chlorhexidine gel and hence shows promising future as an LDD agent in the treatment of periodontal pockets.

Recent advances in periodontal regeneration: A biomaterial perspective

Periodontal disease (PD) is one of the most common inflammatory oral diseases, affecting approximately 47% of adults aged 30 years or older in the United States. If not treated properly, PD leads to degradation of periodontal tissues, causing tooth movement, and eventually tooth loss. Conventional clinical therapy for PD aims at eliminating infectious sources, and reducing inflammation to arrest disease progression, which cannot achieve the regeneration of lost periodontal tissues. Over the past two decades, various regenerative periodontal therapies, such as guided tissue regeneration (GTR), enamel matrix derivative, bone grafts, growth factor delivery, and the combination of cells and growth factors with matrix-based scaffolds have been developed to target the restoration of lost tooth-supporting tissues, including periodontal ligament, alveolar bone, and cementum. This review discusses recent progresses of periodontal regeneration using tissue-engineering and regenerative medicine approaches. Specifically, we focus on the advances of biomaterials and controlled drug delivery for periodontal regeneration in recent years. Special attention is given to the development of advanced bio-inspired scaffolding biomaterials and temporospatial control of multi-drug delivery for the regeneration of cementum-periodontal ligament-alveolar bone complex. Challenges and future perspectives are presented to provide inspiration for the design and development of innovative biomaterials and delivery system for new regenerative periodontal therapy.

Functionalized nanoparticles containing MKP-1 agonists reduce periodontal bone loss

BACKGROUND

Progress over of the past several years has elucidated a role for mitogen-activated protein kinase phosphatase to regulate periodontal inflammation yielding new possibilities for treatment of periodontal diseases. These studies aimed to determine if nanoparticles (NPs) loaded with a pharmacological agent that induces mitogen-activated protein kinase phosphatase have potential clinical utility for management of periodontal inflammation and alveolar bone.

METHODS

Polyethylene glycol (PEG)-polylactide (PLA) (PEG-PLA) NPs were loaded with auranofin (ARN), an antirheumatic drug, to induce mitogen-activated protein kinase phosphatase (MKP)-1 expression in vitro and in vivo. Release kinetics of ARN from NPs was performed by high performance liquid chromatography (HPLC). Fluorescent-labeled NPs were used to show uptake into macrophages by flow cytometry. Real-time quantitative polymerase chain reaction (qPCR) was used to determine dual specificity protein phosphatase (Dusp)-1 mRNA induction by Auranofin-loaded nanoparticles (ARN-NPs) and viability of ARN-NPs was determined by colorimetric in vitro assays. Functional in vitro assays were used to measure functional MKP-1 induction and preclinical models using Aggregatibacter actinomycetemcomitans lipopolysaccharide-induced alveolar bone loss and microcomputed tomography was used to determine in vivo efficacy of functionalized ARN-NPs.

RESULTS

Data indicated that ARN-NPs had reduced cytotoxicity compared with free ARN and Dusp1 mRNA and MKP-1 activity was significantly increased by ARN-NPs in vitro. Flow cytometry indicated rapid uptake into macrophages. Finally, significant bone loss reduction was observed with ARN-NPs compared with control NPs in vivo using an lipopolysaccharide-induced rat model of periodontitis.

CONCLUSION

Results from these studies suggest that developing NPs functionalized with ARN have anti-inflammatory activities and may be a novel adjuvant therapeutic strategy to significantly improve periodontitis therapy and outcomes.

Contribution of Statins towards Periodontal Treatment: A Review

The pleiotropic effects of statins have been evaluated to assess their potential benefit in the treatment of various inflammatory and immune-mediated diseases including periodontitis. Herein, the adjunctive use of statins in periodontal therapy in vitro, in vivo, and in clinical trials was reviewed. Statins act through several pathways to modulate inflammation, immune response, bone metabolism, and bacterial clearance. They control periodontal inflammation through inhibition of proinflammatory cytokines and promotion of anti-inflammatory and/or proresolution molecule release, mainly, through the ERK, MAPK, PI3-Akt, and NF-κB pathways. Moreover, they are able to modulate the host response activated by bacterial challenge, to prevent inflammation-mediated bone resorption and to promote bone formation. Furthermore, they reduce bacterial growth, disrupt bacterial membrane stability, and increase bacterial clearance, thus averting the exacerbation of infection. Local statin delivery as adjunct to both nonsurgical and surgical periodontal therapies results in better periodontal treatment outcomes compared to systemic delivery. Moreover, combination of statin therapy with other regenerative agents improves periodontal healing response. Therefore, statins could be proposed as a potential adjuvant to periodontal therapy. However, optimization of the combination of their dose, type, and carrier could be instrumental in achieving the best treatment response.

Functional assessment of peptide-modified PLGA nanoparticles against oral biofilms in a murine model of periodontitis

The interaction of the periodontal pathogen Porphyromonas gingivalis (Pg) with commensal streptococci promotes Pg colonization of the oral cavity. Previously, we demonstrated that a peptide (BAR) derived from Streptococcus gordonii (Sg) potently inhibited adherence of Pg to streptococci and reduced Pg virulence in a mouse model of periodontitis. Thus, BAR may represent a novel therapeutic to control periodontitis by preventing Pg colonization of the oral cavity. However, while BAR inhibited the initial formation of Pg/Sg biofilms, much higher concentrations of peptide were required to disrupt an established Pg/Sg biofilm. To improve the activity of the peptide, poly(lactic-co-glycolic acid) (PLGA) nanoparticles were surface-modified with BAR and shown to more potently disrupt Pg/Sg biofilms relative to an equimolar amount of free peptide. The goal of this work was to determine the in vivo efficacy of BAR-modified NPs (BNPs) and to assess the toxicity of BNPs against human gingival epithelial cells. In vivo efficacy of BNPs was assessed using a murine model of periodontitis by measuring alveolar bone resorption and gingival IL-17 expression as outcomes of Pg-induced inflammation. Infection of mice with Pg and Sg resulted in a significant increase in alveolar bone loss and gingival IL-17 expression over sham-infected animals. Treatment of Pg/Sg infected mice with BNPs reduced bone loss and IL-17 expression almost to the levels of sham-infected mice and to a greater extent than treatment with an equimolar amount of free BAR. The cytotoxicity of the maximum concentration of BNPs and free BAR used in in vitro and in vivo studies (1.3 and 3.4 μM), was evaluated in telomerase immortalized gingival keratinocytes (TIGKs) by measuring cell viability, cell lysis and apoptosis. BNPs were also tested for hemolytic activity against sheep erythrocytes. TIGKs treated with BNPs or free BAR demonstrated >90% viability and no significant lysis or apoptosis relative to untreated cells. In addition, neither BNPs nor free BAR exhibited hemolytic activity. In summary, BNPs were non-toxic within the evaluated concentration range of 1.3-3.4 μM and provided more efficacious protection against Pg-induced inflammation in vivo, highlighting the potential of BNPs as a biocompatible platform for translatable oral biofilm applications.

BAR-encapsulated nanoparticles for the inhibition and disruption of Porphyromonas gingivalis-Streptococcus gordonii biofilms

Background

Porphyromonas gingivalis adherence to oral streptococci is a key point in the pathogenesis of periodontal diseases (Honda in Cell Host Microbe 10:423–425, 2011). Previous work in our groups has shown that a region of the streptococcal antigen denoted BAR (SspB Adherence Region) inhibits P. gingivalis/S. gordonii interaction and biofilm formation both in vitro and in a mouse model of periodontitis (Daep et al. in Infect Immun 74:5756–5762, 2006; Daep et al. in Infect immun 76:3273–3280, 2008; Daep et al. in Infect Immun 79:67–74, 2011). However, high localized concentration and prolonged exposure are needed for BAR to be an effective therapeutic in the oral cavity.

Methods

To address these challenges, we fabricated poly(lactic-co-glycolic acid) (PLGA) and methoxy-polyethylene glycol PLGA (mPEG-PLGA) nanoparticles (NPs) that encapsulate BAR peptide, and assessed the potency of BAR-encapsulated NPs to inhibit and disrupt in vitro two-species biofilms. In addition, the kinetics of BAR-encapsulated NPs were compared after different durations of exposure in a two-species biofilm model, against previously evaluated BAR-modified NPs and free BAR.

Results

BAR-encapsulated PLGA and mPEG-PLGA NPs potently inhibited biofilm formation (IC50 = 0.7 μM) and also disrupted established biofilms (IC50 = 1.3 μM) in a dose-dependent manner. In addition, BAR released during the first 2 h of administration potently inhibits biofilm formation, while a longer duration of 3 h is required to disrupt pre-existing biofilms.

Conclusions

These results suggest that BAR-encapsulated NPs provide a potent platform to inhibit (prevent) and disrupt (treat) P. gingivalis/S. gordonii biofilms, relative to free BAR.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0396-4) contains supplementary material, which is available to authorized users.

Combining PLGA Scaffold and MSCs for Brain Tissue Engineering: A Potential Tool for Treatment of Brain Injury

Nerve tissue engineering is an important strategy for the treatment of brain injuries. Mesenchymal stem cell (MSC) transplantation has been proven to be able to promote repair and functional recovery of brain damage, and poly (lactic-co-glycolic acid) (PLGA) has also been found to have the capability of bearing cells. In the present study, to observe the ability of PLGA scaffold in supporting the adherent growth of MSCs and neurons in vivo and vitro and to assess the effects of PLGA scaffold on proliferation and neural differentiation of MSCs, this study undertakes the following steps. First, MSCs and neurons were cultured and labeled with green fluorescent protein (GFP) or otherwise identified and the PLGA scaffold was synthesized. Next, MSCs and neurons were inoculated on PLGA scaffolds and their adhesion rates were investigated and the proliferation of MSCs was evaluated by using MTT assay. After MSCs were induced by a neural induction medium, the morphological change and neural differentiation of MSCs were detected using scanning electron microscopy (SEM) and immunocytochemistry, respectively. Finally, cell migration and adhesion in the PLGA scaffold in vivo were examined by immunohistochemistry, nuclear staining, and SEM. The experimental results demonstrated that PLGA did not interfere with the proliferation and neural differentiation of MSCs and that MSCs and neuron could grow and migrate in PLGA scaffold. These data suggest that the MSC-PLGA complex may be used as tissue engineering material for brain injuries.

Guided bone regeneration with asymmetric collagen-chitosan membranes containing aspirin-loaded chitosan nanoparticles

Introduction

Membranes allowing the sustained release of drugs that can achieve cell adhesion are very promising for guided bone regeneration. Previous studies have suggested that aspirin has the potential to promote bone regeneration. The purpose of this study was to prepare a local drug delivery system with aspirin-loaded chitosan nanoparticles (ACS) contained in an asymmetric collagen-chitosan membrane (CCM).

Methods

In this study, the ACS were fabricated using different concentrations of aspirin (5 mg, 25 mg, 50 mg, and 75 mg). The drug release behavior of ACS was studied. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to examine the micromorphology of ACS and aspirin-loaded chitosan nanoparticles contained in chitosan-collagen membranes (ACS-CCM). In vitro bone mesenchymal stem cells (BMSCs) were cultured and critical-sized cranial defects on Sprague-Dawley rats were made to evaluate the effect of the ACS-CCM on bone regeneration.

Results

Drug release behavior results of ACS showed that the nanoparticles fabricated in this study could successfully sustain the release of the drug. TEM showed the morphology of the nanoparticles. SEM images indicated that the asymmetric membrane comprised a loose collagen layer and a dense chitosan layer. In vitro studies showed that ACS-CCM could promote the proliferation of BMSCs, and that the degree of differentiated BMSCs seeded on CCMs containing 50 mg of ACS was higher than that of other membranes. Micro-computed tomography showed that 50 mg of ACS-CCM resulted in enhanced bone regeneration compared with the control group.

Conclusion

This study shows that the ACS-CCM would allow the sustained release of aspirin and have further osteogenic potential. This membrane is a promising therapeutic approach to guiding bone regeneration.

An injectable in situ gel with cubic and hexagonal nanostructures for local treatment of chronic periodontitis

Periodontitis is a chronic bacterial infection, and its effective treatment is dependent on the retention of antibiotics of effective concentrations at the periodontal pockets. In this study, a solution-gel based inverse lyotropic liquid crystalline (LLC) system was explored to deliver metronidazole to the periodontal pockets for local treatment of periodontitis. It was found that the metronidazole-loaded LLC precursor spontaneously transformed into gel in the presence of water in the oral cavity. The low viscosity of the precursor would allow its penetration to the rather difficult to reach infection sites, while the adhesiveness and crystalline nanostructures (inverse bicontinuous cubic Pn3m phase and inverse hexagonal phase) of the formed gel would permit its firm adhesion to the periodontal pockets. The LLC system provided sustained drug release over one week in vitro. Results from in vivo study using a rabbit periodontitis model showed that the LLC system was able to maintain the metronidazole concentrations in the periodontal pockets above the minimum inhibition concentration for over 10 days without detectable drug concentration in the blood. Owing to the spontaneous solution-gel transition in the periodontal pockets and unique liquid crystalline nanostructures, the LLC in situ gel provided effective treatment of periodontitis for a prolonged period of time with reduced systematic side effects, compared to metronidazole suspension which was effective for 24 h with detectable metronidazole concentrations in the blood after 6 h.

Autotemplate Microcapsules of CaCO3/Pectin and Nonstoichiometric Complexes as Sustained Tetracycline Hydrochloride Delivery Carriers

New types of composites were obtained by an autotemplate method for assembling hollow CaCO₃ capsules by using pH-sensitive polymers. Five pectin samples, which differ in the methylation degree and/or amide content, and some nonstoichiometric polyelectrolyte complex dispersions, prepared with the pectin samples and poly(allylamine hydrochloride), were used to control the crystal growth. The morphology of the composites was investigated by scanning electron microscopy, and the polymorphs characteristics were investigated by FTIR spectroscopy. The presence of the polymer in the composite particles was evidenced by X-ray photoelectron spectroscopy, particle charge density, and zeta-potential. The new CaCO₃/pectin hollow capsules were tested as a possible matrix for a tetracycline hydrochloride carrier. The kinetics of the drug release mechanism was followed using Higuchi and Korsmeyer-Peppas mathematical models.

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide-co-glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA–lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV–Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA–lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA–lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA–lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA–lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA–lovastatin (100 μg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA–lovastatin (100 μg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA–lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA–lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.

Poly(Lactic-co-Glycolic Acid): Applications and Future Prospects for Periodontal Tissue Regeneration

Periodontal tissue regeneration is the ultimate goal of the treatment for periodontitis-affected teeth. The success of regenerative modalities relies heavily on the utilization of appropriate biomaterials with specific properties. Poly (lactic-co-glycolic acid) (PLGA), a synthetic aliphatic polyester, has been actively investigated for periodontal therapy due to its favorable mechanical properties, tunable degradation rates, and high biocompatibility. Despite the attractive characteristics, certain constraints associated with PLGA, in terms of its hydrophobicity and limited bioactivity, have led to the introduction of modification strategies that aimed to improve the biological performance of the polymer. Here, we summarize the features of the polymer and update views on progress of its applications as barrier membranes, bone grafts, and drug delivery carriers, which indicate that PLGA can be a good candidate material in the field of periodontal regenerative medicine.

A review of drug delivery systems based on nanotechnology and green chemistry: green nanomedicine

This review discusses the impact of green and environmentally safe chemistry on the field of nanotechnology-driven drug delivery in a new field termed "green nanomedicine". Studies have shown that among many examples of green nanotechnology-driven drug delivery systems, those receiving the greatest amount of attention include nanometal particles, polymers, and biological materials. Furthermore, green nanodrug delivery systems based on environmentally safe chemical reactions or using natural biomaterials (such as plant extracts and microorganisms) are now producing innovative materials revolutionizing the field. In this review, the use of green chemistry design, synthesis, and application principles and eco-friendly synthesis techniques with low side effects are discussed. The review ends with a description of key future efforts that must ensue for this field to continue to grow.

Injectable scaffolds: Preparation and application in dental and craniofacial regeneration

Injectable scaffolds are appealing for tissue regeneration because they offer many advantages over pre-formed scaffolds. This article provides a comprehensive review of the injectable scaffolds currently being investigated for dental and craniofacial tissue regeneration. First, we provide an overview of injectable scaffolding materials, including natural, synthetic, and composite biomaterials. Next, we discuss a variety of characteristic parameters and gelation mechanisms of the injectable scaffolds. The advanced injectable scaffolding systems developed in recent years are then illustrated. Furthermore, we summarize the applications of the injectable scaffolds for the regeneration of dental and craniofacial tissues that include pulp, dentin, periodontal ligament, temporomandibular joint, and alveolar bone. Finally, our perspectives on the injectable scaffolds for dental and craniofacial tissue regeneration are offered as signposts for the future advancement of this field.